“Current scientific knowledge does not substantiate your assertions” recently made that climate change is causing more extreme weather events (such as last month’s disastrous Hurricane Sandy), and that the cost of continued inaction on climate change will be very high.

The open letter continues: “The hypothesis that our emissions of CO2 have caused, or will cause, dangerous warming is not supported by the evidence. The incidence and severity of extreme weather has not increased. There is little evidence that dangerous weather-related events will occur more often in the future. ”

I will leave it to others to opine whether or not the signatories to the open letter making these statements are credibly “qualified in climate-related matters”, as they claim for themselves.

For the record, a much larger body of people doubtlessly “qualified in climate-related matters” would surely strongly disagree with this letter. Thousands of experts are quite confident that climate change is in fact a serious future threat to the planet (all species, not just humans), that its economic and social (and biological) costs will be high, and that effective actions can be taken to reduce the impacts.

Here’s the rub: it doesn’t matter that ten or twenty times as many experts of at least comparable quality can be amassed on the other side of the issue to outweigh the signatories of this open letter.

Notwithstanding the vast body of evidence concerning climate change, there are in fact certain elements of climate science that are admittedly unknown or not well understood. Even the IPCC experts would agree. And, because of that, it is in fact somewhat inappropriate to say cavalierly, as Ban Ki-Moon and others such as Al Gore have said, that “the science is settled.”

Even though assembling a vast quantity of data and analyses make for a damn persuasive case to most reasonable people, the science is not, fully, settled. In fact, given the daunting complexity of the global climate system, that will surely always be the case.

Those with closed minds — who for whatever reason choose to ignore the preponderance of evidence and focus instead on the exceptions — will not concede the likelihood of climate change. To them, the outliers and unknowns mean that there could theoretically be a possibility that human-driven climate change isn’t really happening, ergo let’s not get worried about it until it can be proven (which, for them, will generally be never).

As a result, stalemate exists. This is just fine for climate deniers and those who have a vested interest in maintaining the status quo — the former often being funded by the latter.

Extreme flip statements like “the science is settled” only harden the opposition. It’s not the first time, and certainly won’t be the last, that too-strident environmentalists have harmed rather than helped the causes about which they care.

The open letter to Ban Ki-Moon does, however, have one notable redeeming feature. It is found in the last sentence: “Climate policies therefore need to focus on preparation for, and adaptation to, all dangerous climatic events however caused.”

This inarguable position in favor of improving our adaptation capabilities is an increasing focus of the climate debates.

The stalemate on climate change policy means that chances are growing that our time is shrinking to do anything meaningful to prevent significant future climate change. Accordingly, the best we may be able to do is to agree to limit the impacts that more severe weather would create.

We can argue about whether weather severity is on the rise. However, if we waste our time arguing about that (which we are), we will have less time to spend on actually preparing more prudently for the future — whether it’s as worrisome as many climate scientists think it will be, or it’s a “don’t worry, be happy” world just like today’s.